The present invention relates, generally, to sheet processing equipment for transporting signatures moving in serial fashion along a path to one of a plurality of collation paths and, more particularly, to sheet processing equipment for collation of printed signatures to be used in the binding of a publication such as a magazine or a newspaper. The present invention relates to an apparatus for decelerating substantially evenly spaced apart successive signatures found in a stream of fast moving signatures for delivery of the signatures to a subsequent process such as a rotary fan delivery device. The present invention also relates to an apparatus for guiding successive signatures from a slow down mechanism of the foregoing kind to a downstream destination such as a rotary fan delivery device. The present invention provides an improved signature delivery system for a high speed printing press which allows for increased operating speeds with fewer jams while, at the same time, reducing or preventing damage to the signatures as the signatures travel through sheet processing equipment.
Sheet processing equipment contemplated herein may range from apparatus associated with an office copier, to sheet or web handling devices employed in the manufacture of paperboard articles, to sheet processing equipment specifically adapted to process signatures to be used in binding or otherwise assembling books, magazines or newspapers. Each of these environments presents a somewhat different challenge in designing an efficient collator or delivery system, but the same objective applies to the entire class of apparatus, namely, accurately routing selected flexible webs or ribbon sections along a desired collation path to achieve a desired order.
In the printing industry, an image is repeatedly printed on a continuous web or substrate such as paper. The ink is dried by running the web through curing ovens. In a typical printing process, the web is subsequently slit (in the longitudinal direction which is the direction of web movement) to produce a plurality of continuous ribbons. The ribbons are aligned one on top of the other, folded longitudinally, and then cut laterally to produce a plurality of multipaged, approximately page length web segments, termed signatures. A signature can also be one printed sheet of paper that has or has not been folded. It is often desirable to transport successive signatures in different directions along different paths in order to increase the overall operating speed and versatility of the printing process. In general, a sheet diverter operates to route fast moving signatures along a desired one of a plurality of paths as the signatures continue on to the next step in the signature processing system.
Printing press systems are operable at high speeds, typically in excess of 2,000-3,000 feet per minute (fpm). It is often desirable to run printing press equipment at the highest speeds possible in order to produce as many printed products as possible in a given amount of time. Because printing presses operate at high speeds, it is usually, if not always, necessary to reduce the speed of the signatures in the delivery system in order to shingle and to square the signatures and eventually stack the signatures. Various delivery systems for decelerating and shingling signatures are set forth in the prior art.
A system which employs a rotary fan delivery system is found after signature decelerating equipment to individually collect the signatures and subsequently pass each signature to a conveyor, such as a shingling conveyor. Generally, signatures are caused to fall or move into a receptive slot in the rotating fan-like delivery means. As the rotary fan rotates, the signatures fall out one after the other typically onto a slow moving conveyor in an overlying or shingled arrangement. Without signature decelerating equipment, in order to avoid damage to the signatures as the signatures are thrown into the respective slots of the rotary fan device, the speed of each signature must be generally slowed down by running the printing press and folder at a slower rate of speed so that the impact force of the leading edge of the signature against a dead end surface of the slot is reduced. Thus, without a slow down mechanism, reduced operating speeds limit the overall output of the printing system.
A problem which may occur when using a rotary fan delivery system concerns adequately controlling the path of each signature as the signatures are transferred from a slow down device to the rotary fan delivery system. In such systems, signatures generally fall from the slow down device to the rotary fan device. Stated differently, the signatures may be unsupported or unguided during this transfer step. Unsupported signatures have a tendency to freely flap, fold over, tear or be damaged in other different ways, or have a tendency to move to the wrong destination. The greater the distance between a slow down device and a fan delivery system, the more likely an unsupported signature will be damaged as it enters or attempts to enter the fan delivery system thereby causing jams in the overall process resulting in down time and repair expenses.
Yet another problem of utilizing a delivery system concerns guiding the signatures from a slow down mechanism to a subsequent processing device. Often, when a signature travels through a processing system between two signature transport tapes, the signature may tend to cling to one or both of the two tapes during the transition stage, instead of continuing on in a straight or substantially straight path to subsequent processing equipment. When a signature improperly follows a tape path and travels to the wrong place in the processing system, a jam can occur which results in the shut down of the entire printing production system until the jam is cleared.
Still another problem of such a delivery system concerns correctly timing the transfer of the signatures from one step in the printing process, such as a slow down step, to a subsequent step, such as a fan delivery step. If a respective signature slot in a rotary fan delivery device is not properly aligned with a signature emerging from a slow down mechanism at the appropriate time, a signature will be directed at the fan delivery device in such a way that the signature will not properly enter the rotary fan device which may cause a jam in the overall operation.
Although the problems described above generally correlate to a processing system which employs a rotary fan delivery device, the same or similar problems can occur in other delivery systems which utilize slow down mechanisms followed by other known processing equipment. The present invention may be utilized in various delivery systems for decelerating signatures and transferring the signatures to further processing equipment such as, for example, shingling devices or stackers, known to those skilled in the art.
Accordingly, there is a need for a sheet processing system that is capable of operating at high speeds, e.g., speeds in excess of 2,500-3,000 fpm and above, and yet is also capable of providing signatures that are acceptable in quality. What is needed is a delivery system which reduces the speed of signatures traveling through the processing system while allowing for an increased overall operating speed of the sheet processing system. What is also needed is a sheet processing system which increases control over signatures during a decelerating process and during transport of the signatures to a subsequent processing step.
In accordance with one embodiment of the present invention, a sheet diverter receives a fast moving stream of regularly spaced apart signatures from a sheet processing system. The sheet diverter sends the signatures down one of a plurality of collation paths. A signature slow down mechanism is positioned within the collation path such that as a signature travels down the collation path, the signature slow down mechanism grabs a tail end of the signature to slow down the speed of the signature. A pair of rotating cam lobes lying in general face-to-face relation along the collation path effectively reach into the collation path at the appropriate moment to grab the trailing end of the signature therebetween.
In a preferred embodiment, a pair of opposed tapes circulating in separate endless loops through the slow down mechanism and confining a signature therebetween, deliver the signature to the slow down mechanism which comprises a pair of counter-rotating independently driven roller or cam assemblies. The slow down mechanism has a lineal speed that is less than the lineal speed of the signatures so as to reduce the speed of the signatures as they are grabbed by the slow down mechanism.
In accordance with another embodiment of the present invention, regularly spaced apart signatures traveling at an original speed along a travel path are alternately diverted into a selected one of a plurality of collation paths to create a larger space between successive signatures in the selected paths after which the signatures are decelerated prior to being transferred to a subsequent process. The signatures are decelerated such that the leading edge of a trailing signature traveling down a selected one of the paths of signatures does not contact the trailing edge of a leading signature traveling down the same path as the leading signature is slowed down and the trailing signature continues on toward the slow down device.
In accordance with yet another embodiment of the present invention, a signature slow down mechanism is provided to decelerate the speed of individual signatures traveling along a path on their way to a further processing step in an overall sheet handling system. The slow down mechanism is positioned at the end of a collation path and is designed to be positioned as close as possible to the next device in the sheet handling system so as to increase control over the signatures as the signatures are transferred from one piece of equipment to another.
In accordance with still another embodiment of the present invention, a signature slow down assembly is provided along a path in which signatures travel on their way to further processing equipment in an overall sheet handling system. The signature slow down mechanism is capable of being opened and closed with respect to the path of the traveling signatures in order to clear away jams which may occur in the sheet handling system prior to, in or near, the signature slow down assembly. In addition, for those types of products produced in a printing press system which do not require the use of a slow down mechanism or need the advantages provided thereby, the adjustable, movable slow down mechanism can be, in effect, disengaged by moving the slow down device away from the signature path.
In a preferred embodiment, the signature slow down mechanism is capable of further adjustment so as to increase or decrease the gripping force applied to a signature as the signature is slowed down by the slow down mechanism.
In accordance with another embodiment of the present invention, a method for transporting signatures traveling at an original speed along a travel path through a sheet processing system is provided. The signatures are delivered to a slow down mechanism in which the speed of the signatures is reduced. The signatures are then fed to a further processing step. The original speed and position of the signatures, the position and operation of the slow down mechanism and the position and operation of the further processing equipment are phased in relation to each other so as to prevent or minimize damage to the signatures and increase the overall operating speed of the processing system.
In a further embodiment of the present invention, a signature guiding device is positioned intermediate of a signature slow down mechanism and a further delivery device. The guiding device is designed to prevent a signature from traveling along a wrong path as the signature is transferred from one device to the next. Preferably, the guiding device comprises a stripping signature eject idler roller which effectively strips a signature from a group of belts traveling in an endless loop in a processing system allowing the signature to properly continue on to the next step. An air blowing system may be used in combination with the eject idler roller or alternatively, by itself, to expel air in an appropriate manner thereby assisting in the control over the signatures as the signatures move from one device to another.
Accordingly, it is a general feature of the present invention to provide an apparatus for receipt of signatures from a high speed printing press and for slowing down the signatures to decrease signature damage, reduce jams and increase the overall operating speed of a sheet processing system.
Another feature of the invention is to provide a signature delivery system which is useful for a wide range of paper types and products over a wide range of press speeds and which is also useful in combination with diverter systems and signature discharge systems without significant modification to those systems.
Yet another feature of the present invention is to provide an improved signature delivery system which is easy to operate, easy to service, economical to manufacture and is relatively simple to construct and assemble.
Still another feature of the present invention is to provide a sheet processing system which increases control over signatures as the signatures travel from one processing step to another thereby decreasing signature damage, jams in the operating equipment and increasing overall speed of a printing press operation.
A further feature of the present invention is to provide a slow down mechanism that provides consistent, substantially non-varying signature transfer timing to subsequent processing equipment in a sheet handling system such as, for example, a rotary fan delivery system.
Yet, a further feature of the present invention is to effectively transfer signatures from a slow down mechanism to subsequent equipment in a sheet processing system thereby achieving the advantages provided for herein.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings.